What do the following two equations represent? $x+3y = -4$ $-3x+y = -2$
Solution: Putting the first equation in $y = mx + b$ form gives: $x+3y = -4$ $3y = -x-4$ $y = -\dfrac{1}{3}x - \dfrac{4}{3}$ Putting the second equation in $y = mx + b$ form gives: $-3x+y = -2$ $y = 3x-2$ The slopes are negative inverses of each other, so the lines are perpendicular.